A massive power failure swept the United States and southern Canada from the Great Lakes to the Eastern Seaboard yesterday, shuttering businesses, stranding commuters in elevators and subway cars, and leaving government officials bewildered as to the cause of the largest electrical outage in the nation's history.
The blackout struck just after 4 p.m. and quickly incapacitated traffic lights, airports, trains, computer systems and air conditioners throughout a broad swath from the Midwest to the Atlantic Ocean. Detroit, Cleveland, Toronto and New York were flooded with sweltering office workers who poured out of lifeless skyscrapers and subways into a teeming scene of urban confusion and discontent.
Maryland was mostly spared from the imbroglio, though the University of Maryland's College Park campus lost power for about 20 minutes. Gov. Robert L. Ehrlich Jr. referred to the outage as little more than "a pretty interesting exercise for us."
But northward into Canada and throughout much of the nation's most densely populated region, the wave of frustration and near-panic evoked memories of the 2001 terrorist attacks, with millions of Americans watching television images of stunned New Yorkers filing out of the city on foot. Reminiscent of New York's Sept. 11 lockdown, traffic was turned back at the bridges and tunnels entering Manhattan, and the outbound rush hour descended into gridlock.
"The whole time we were thinking, `Maybe this is the first stage. Maybe something is going to happen after this,' " said Claire Mysko, 26, who was evacuated from her Wall Street office building and had to walk through hordes of commuters to her 14th Street apartment.
"It makes you wonder - was this terrorism or what?" said John Meehan, 56, exhausted after a 37-story descent from his Cleveland office tower.
Perhaps keen to those anxieties, officials in New York and other cities moved quickly to dispel any concern that terrorism was to blame - even as they confessed to having few clues about the cause. Several state and federal officials said no evidence of terrorism was found.
New York Mayor Michael R. Bloomberg pledged: "Tomorrow, we'll be back up to business as usual."
"The one thing I think I can say for certain is that this was not a terrorist act," President Bush said, adding that "slowly but surely we're coping with this massive, national problem."
While the cause was unclear, officials in the United States and Canada seemed to be focusing on an area along the New York/Canada border near Lake Erie as the possible root of the troubles - and disagreeing on which side of the border was at fault. American officials were skeptical of a Canadian claim that lightning triggered the cascade of events when it hit a power plant on the U.S. side of Niagara Falls.
A lightning strike or failed transformer can trigger a surge in power demand or destabilize the flow of power through the grid that supplies electricity to cities and homes across the nation, but the system is designed to absorb and compensate for such fluctuations.
"It happened in about 9 seconds," Michehl R. Gent, president of the industry-sponsored North American Electric Reliability Council, said on CNN. "The system is supposed to be designed so that doesn't happen." He said it is essential to find out why the grid collapse occurred so rapidly and was so widespread, with a loss of 10 percent of the electricity flowing east of the Rocky Mountains.
"We'll find out here what caused the blackout," Bush said. "But most importantly what we now need to do is fix the problem and to get electricity up and running as quickly as possible."
Airports in New York, Cleveland and southern Canada were closed, lacking the metal detectors and ticket counters necessary to stay in business. Air traffic control centers switched to backup power to guide in planes that were in the air, and service to the airports was being gradually restored as the day wore on.
Trains on Amtrak's busy Northeast rail corridor, which run on electricity, were halted north of Philadelphia.
In New York City, millions of people poured out of office buildings and the crippled subway system into a darkened streetscape that evoked memories of the 1977 blackout that plunged the city into two days of looting, fires and chaos. But Bloomberg said the latest blackout had prompted no significant fires and "no criminal activity of any size."
Consolidated Edison, which provides power to New York City, said late last night that bringing back all the city's lights was still a "several-hour process." Spokesman Michael Clendenin said ConEd was not sure all its customers would have power by morning.
The Long Island Power Authority said it had restored power to 150,000 of its 1.1 million customers by 10 p.m.